1. Field of the Invention
The present invention relates to an engine having a cylinder head and rocker box with a relief duct system that redirects and reduces gases flowing past the piston and engine.
2. Description of the Prior Art
Internal combustion engines produce gases in the combustion chamber that are forced under pressure past the piston and into the engine's crankcase. Such gases are typically an oil-laden mist and are often referred to as “blow-by” gas. The piston motion causes pressure fluctuations in the crankcase forcing the blow-by gases to be routed back toward the engine carburetor. Such leakage leads to accumulations of oil in the combustion chamber and elsewhere and may interfere with engine operation. Such blow-by may also lead to a buildup on the air filter and a decrease in engine performance. The air filter, seals and other components may have to be replaced after a much shorter interval due to blow-by.
To overcome this problem, systems have been developed that provide for a breather system such as shown in U.S. Pat. No. 6,345,613. That breather system utilizes an open channel formed in the upper surface of the cylinder head. The channel allows for breathing and for the oil mist laden air to flow through the channel and other passages. However, the system shown in U.S. Pat. No. 6,345,613 requires formation of several connecting passages and an arcing channel that must be formed in the upper surface of the cylinder head in a complicated machining operation. Such a system has proven to be difficult to machine and the formation of a long channel may weaken the cylinder head. The system in U.S. Pat. No. 6,345,613 also relies on passive breathing to atmosphere, rather being drawn by a vacuum to remove the blow-by gases.
It can be appreciated that a blow-by removal system is needed that overcomes the problems associated with the prior art. Such a system should provide for simple manufacture and positive removal of the blow-by gases. Such a system should provide for improved removal efficiencies while maintaining the structural integrity of the cylinder head and avoiding difficult to manufacture channels. The present invention addresses these as well as other problems associated with removal of blow-by gases in internal combustion engines.